Abstract: A dual purpose valve assembly may comprise a conduit, a first valve, and a second valve. The first valve may comprise a vacuum breaker valve. The second valve may comprise a check valve. A drain system may comprise a supply tube, a drain tube, and a dual purpose valve disposed between the supply tube and the drain tube. The drain system may allow fluid to drain based on gravity alone, and the dual purpose valve assembly may operate based on gravity alone.

Abstract: A sanitary system for a locomotive wherein the treatment tank is protected from freezing by the use of the heat available in the exhaust air removed from the toilet compartment. A sealed and insulated compartment is formed around the treatment tank, and a vent is connected between the toilet room and the insulated compartment. A suction line located at an opposed position in the insulated compartment is used to direct the flow of air from the toilet room, through the insulated compartment around the treatment tank, to the locomotive exterior. By eliminating the need for heat tracing of the treatment tank, this invention reduces the cost and energy usage of the locomotive sanitary system.

Abstract: A tank ventilation exhaust fan having the unique ability to provided positive exhaust on a continuous basis while diluting the contaminated air and vapors, being emitted by the tank, with fresh air at a ratio in excess of five to one. A mixing chamber within the fan housing allows the fan to mix fresh air with vapors from the tank and expel the mixture over several hours. An alternate embodiment allows for continuous dilution of the tank's vapors.

Abstract: A vacuum toilet system for a transport vehicle includes a toilet bowl, a sewage collection system, a normally closed sewer valve connecting the toilet bowl to the sewage collection system, a vacuum generator for exhausting air from the sewage collection system to create a partial vacuum in the sewage collection system of a magnitude sufficient for providing effective transport of sewage from the toilet bowl into the sewage collection system, and an odor removal device for removing odiferous material from the air exhausted from the sewage collection system. The odor removal device is disconnected when the transport vehicle is moving at a speed that exceeds a given limit value.